The 50-year-old comedian detailed the experience on her blog Monday, saying sudden nausea, aches and other symptoms pushed her to do an online search for "women's heart attack symptoms." She took a few aspirin and went to a cardiologist the next day.
She says an artery was 99 percent blocked and a stent was inserted.
O'Donnell writes in a kind of verse on her blog. She says: "Know the symptoms ladies/ listen to the voice inside/ the one we all so easily ignore."
The comedian recently hosted "The Rosie Show" on the Oprah Winfrey Network. It was canceled in March.